Make filenames from dir name

[batteryviewer] / batteryviewer.c

diff --git a/batteryviewer.c b/batteryviewer.c
index 1c38b3cca8527a36052023be1d85a54c5863c453..9f1dedd8791a94630a302a9d15e9b34c011b6c3c 100644 (file)
--- a/batteryviewer.c
+++ b/batteryviewer.c
@@ -1,15 +1,30 @@
+// For vasprintf
+#define _GNU_SOURCE
+
 #include "chart.h"
 #include <ctype.h>
 #include <errno.h>
 #include <gtk/gtk.h>
 #include <math.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 
-const char voltage_filename[] = "/sys/class/power_supply/BAT0/voltage_now";
-const char current_filename[] = "/sys/class/power_supply/BAT0/current_now";
+char *sasprintf(const char *fmt, ...) {
+  char *result;
+  va_list args;
+  va_start(args, fmt);
+  if (vasprintf(&result, fmt, args) == -1) {
+    fprintf(stderr, "Can't allocate memory!?\n");
+    abort();
+  }
+  va_end(args);
+  return result;
+}
 
 struct State {
+  char *voltage_filename;
+  char *current_filename;
   BVChart *voltage;
   BVChart *current;
 };
@@ -42,9 +57,9 @@ static float fatof(const char *filename) {
   return val;
 }
 
-static gboolean collect_data(struct State *state __attribute__((unused))) {
-  fprintf(stderr, "Voltage: %f, current: %f\n", fatof(voltage_filename),
-          fatof(current_filename));
+static gboolean collect_data(struct State *state) {
+  fprintf(stderr, "Voltage: %f, current: %f\n", fatof(state->voltage_filename),
+          fatof(state->current_filename));
   return TRUE;
 }
 
@@ -80,7 +95,11 @@ static void activate(GtkApplication *app, gpointer user_data) {
 }
 
 int main(int argc, char **argv) {
-  struct State state;
+  char *battery_dir = "/sys/class/power_supply/BAT0";
+  struct State state = {
+      .voltage_filename = sasprintf("%s/voltage_now", battery_dir),
+      .current_filename = sasprintf("%s/current_now", battery_dir),
+  };
 
   GtkApplication *app = gtk_application_new("com.scottworley.batteryviewer",
                                             G_APPLICATION_DEFAULT_FLAGS);